Drought-affected graziers in Queensland have requested a three-month extension to a national park access agreement to keep their cattle alive.

A deal to allow graziers to use the pastures in national parks was struck between the Queensland Department of Agriculture and the Federal Department of National Parks in June, on the condition the cattle would be removed from the reserves by December 31.

However with still no substantial rain falling, those using the national parks are becoming more concerned over what to do with their cattle in the new year.

Grazier, John Gilmore, has had about 500 head of breeder cattle in the Moorrinya National Park, 400 kilometres west of Townsville, for four months.

He says he's been investing a lot of time and money in carting water to the National Park to keep them there.

Mr Gilmore says the access agreement has kept his cattle alive but if it doesn't rain before December he'll struggle to keep the stock.